Two popular frameworks exist for paying down multiple debts: the avalanche and the snowball.
Avalanche (mathematically optimal). Direct all extra payments to the highest-interest-rate debt while making minimums on others. When it's paid off, roll that payment to the next highest-rate debt. This minimizes total interest paid — the highest-rate debt is the most expensive dollar-for-dollar, so eliminating it first saves the most money.
Snowball (psychologically driven). Target the smallest balance first, regardless of interest rate. The quick win of eliminating an account can build momentum and motivation — studies suggest some people are more likely to stay on track when they experience early victories.
When do they produce the same result? If all debts have the same interest rate, or if you only have one debt, both strategies are identical.
The real cost of the snowball. In most scenarios with different interest rates, the avalanche saves both interest and time. The snowball's cost is the extra interest paid by ignoring the high-rate debt while focusing on a lower-rate small balance.
Combining strategies. Some people use a hybrid: pay off the smallest balance first if it's close to elimination (e.g., 2–3 months away), then switch to avalanche discipline for the remaining debts.